I need to sign & verify an message on Ethereum, but my problem is that I only have my account address. When I try to use for instance MyCrypto it requires another type of wallet. I have tried other apps but none seems to allow for signing based on solely the Account address. Does anyone have any tips if this is possible?
As Lauri says it is not possible to sign it. My problem was that I participated in the Polkadot ICO without an Ethereum wallet, I used some web pages or something. But after looking through my files I found an JSON file having my ethereum address and various other data. When I opened this file with MyCrypto I was finally able to sign my Ethereum transaction.